Yes, it's sustainable because no foods become "forbidden".

I have been doing this diet for 6 weeks and in that time have lost 6 pounds. It already doesn't feel like a diet but a way of life, I actually look forward to my fast days to give me body a break from digesting food. I am finding my appetite on non-fasting days is gradually decreasing as I am more aware of whether I am hungry or not. Six weeks into most other diets I have tried I am usually bored and grumpy and ready to give it all in, despite having lost more weight. I would be craving pizza and wine and things, with this way of eating I'm having the things I like if I fancy them and as a results not craving them constantly.

I would starve

Diets that temporarily change your habits don't work, the weight comes back and usually then some more. Fasting can't be kept up indefinitely so its not a healthy option. Besides I would get too hungry from not eating and then binge eat. So that would make the problem worse anyway.

I Have No Interest.

I really have nothing to gain by trying a fad diet such as the Fast Diet. I simply subscribe to the age-old belief that I simply will try to burn more calories than I consume. If I am able to do so, I will lose weight. If not, I will gain weight.

No, I will not be trying the Fast Diet.

I was always told by my personal trainer that fasting diets are unhealthy; losing weight should be gradual. I also learned that after the fast diet is over, it is harder to keep the weight off. In some cases, people put on some extra pounds. So I rather would not try this new way of dieting.